In order to meet the miniaturization and integration requirements for future integrated circuits (ICs), the rapid development of IC manufacturing technology has continuously reduced the sizes of semiconductor devices in ICs. Specifically, the dimensions of metal oxide semiconductor (MOS) devices have been steadily reduced. Transistor is one of the important components in MOS devices.
With continuous decrease in the size of semiconductor devices, conventional dielectric layer made of SiOx or SiON may not be able to meet the performance requirements for semiconductor devices. In particular, transistors containing a dielectric layer of SiOx or SiON may demonstrate a variety of problems, such as current leakage, impurity diffusion, etc. Such problems may affect the threshold voltage of the transistor and may further reduce the reliability and the stability of the transistor.
To solve these problems, a transistor comprising a high-k dielectric layer and a metal gate, i.e. a high-k metal gate (HKMG) transistor, has been proposed. The HKMG transistor replaces conventional SiOx or SiON with a high-k dielectric material for the dielectric layer. In addition, the HKMG transistor also replaces conventional polycrystalline silicon with a metal or a metal compound for the formation of the gate electrode. With a reduced size, the HKMG transistor may demonstrate a series advantages, such as low current leakage, low operation voltage, low energy consumption, etc. Therefore, the performance of the transistor may be improved.
However, together with the decrease in the size of semiconductor devices, undesired influence of the high-k dielectric layer and the metal gate on the semiconductor devices may also become severe. The disclosed Fin-field effect transistor (Fin-FET) device and the fabrication methods are directed to solve one or more problems set forth above and other problems in the art.